Abstract: An automatic shipboard collision avoidance system comprises radar; a situation indicator connected to the radar receiver; a computer, which extracts target echoes from clutter and determines the coordinates and motion parameters of targets; an interface through which the computer is connected to the situation indicator; a target tracking gate unit connected via the interface to the computer and having a count pulse generator, a current range counter, range comparison circuits, a gate generator and a signal-half gate generator; a video signal encoder connected to the radar and, via said interface, to said computer and having a threshold circuit, a quantizer, a selector and a buffer storage. A control signal unit generates control signals to control the gain of the radar and sign characters of the count pulses and is connected through the interface to the computer. Usually, noise would be a problem in rough seas or in the presence of intense hydrometeors.